I think that there should be a place for MCpl's to hang out, separate from the soldiers. In the LdSH, they have the Green Point Lounge rest area, and I have heard some other units have similar set-ups. Why? So that they can relax, and let their hair down, so to speak, without worrying about some Tpr or Cpl overhearing the MCpl talk about another soldier. We had our own tent lines for MCpl's in Bosnia (jn our Sqn), and I think it was very effective, as it allowed the soldier's to vent without the MCpl overhearing, and vice versa. I know when I was a Tpr I thought it was bullshit for the MCpl's to have their own mess in Cyprus, but then again I was only a Tpr and didn't understand these things.
I also agree regarding once promoted a MCpl should move to another troop or Sqn, but it can depend on circumstances, obviously. In some ways it would be better for them to stay put, as they are more comfortable in that environment and it will make for an easier transistion, but the familiarity aspect can also impede the enforcement of discipline.
In this same vein, I think that when an NCM CFR's or goes the UTPNCM route, they should have to rebadge (assuming they stay in same trade of course) or move to another unit/brigade etc. Moreso at the Cpl/MCpl/Sgt rank level to 2LT/Lt, because there would be too many pers who were far too familiar with that soldier when they were an NCM, and then when they come back as an officer, they are at a disadvantage, IMO.
Al